Sodium is used extensively in the human body for a variety of activities.(2*) Inside our bodies, the sodium is dissolved in water and becomes an ion (this means it carries a charge).

Sodium works together with potassium to create gradients. That is, the two ions work together to create a transport system that exploits a fundamental principle of fluid dynamics:(3*)

Substances naturally flow from areas of most concentration to areas of least concentration. Your body can use sodium groupings to draw water or molecules into and out of cells.(4*) This is an oversimplification, but it's only meant to give you an overview of one of the many functions sodium has within the human body.

Potassium works alongside sodium to create potential not only for the movement of chemicals but also for the transmissions of nerve impulses.

Sodium deficiency is quite rare and usually only affects the very ill or those who exercise for prolonged periods of time (e.g. marathon runners).(5*)Symptoms include weakness, nausea, and muscle cramps.(6*)